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Avisornis
Avisornis is a genus of moderately-sized Late Cretaceous carnivorous dromaeosaurids. Note: Avisornis is not a real dinosaur. Please do not think it is. Description The Avisornis was a small, lithe dinosaur. It bore the long legs of an ornithomimid, but with the one long, sickle-shaped claw on its feet. Like all other dromaeosaurids, Avisornis was feathered. It is unknown if it was covered in dino-fuzz or bore true feathers, but recent fossil evidence has shown that it had feathers similar to those of today's birds on its arms and tail. These, however, were either used for insulation or display instead of true flight. Discovery Avisornis was discovered around a year ago on "Raptor Island", which is known for its abundant dromaeosaurid fossils. Back in the Late Cretaceous, Raptor Island was a part of Laramidia, the western side of North America when it was divided by the Western Interior Seaway. On Raptor Island, paleontologists found hundreds of Avisornis packed together, all at different stages of maturity. They decided that the Avisornis had been washed there during a flood during seperate times, since the rest of the Avisornis fossils they uncovered were in groups of four, five, or six. Classification Avisornis is part of the subfamily Velociraptorinae, which is the subfamily for all dinosaurs more related to Velociraptor than to Dromaeosaurus. When discovered, Avisornis was placed in Ornithomimidae, when the paleontologists had recovered only a few bones: the tailbones, arms, and legs (without the sickle-claw). When half of a skeleton of a sub-adult was uncovered, they made it another species of Velociraptor, V. laramidiensis. During another dig on Raptor Island, a team of paleontologists stumbled upon the cluster of Avisornis fossils, and finally had a clear picture of its anatomy. They gave it its own genus, and placed it in the Velociraptorinae. * Kingdom: Animalia * Phylum: Chordata * Clade: Dinosauria * Order: Saurischia * Suborder: Theropoda * Family: Dromaeosauridae * Clade: Eudromaeosauria * Subfamily: Velociraptorinae * Genus: Avisornis * Type Species: A. laramidiensis * Species: A. laramidiensis, A. appalachiensis, A. australiensis Paleobiology Like all other carnivores, Avisornis had sharp teeth for biting into meat. What was more useful was it's sickle-shaped claw, a feature found in all dromaeosaurids. Avisornis's claw was first thought to be used to slash through its prey- after all, a large claw like that could inflict a fatal wound if sliced through flesh. But a fossil showing an Avisornis stabbing its claw into a hadrosaur dinosaur's neck showed that it wasn't used for slicing, but for stabbing its prey's neck to kill it. Feathers The feathers on Avisornis, based on studies, were a dark blueish-black color. There were rings of yellow on the tail and body. It was hard for this dinosaur to camouflage in the open, but because of its small size, could simply hide behind a bush and hope its victim didn't spot it. The feathers on Avisornis's body were most likely just dino-fuzz or proto-feathers, but the arms bore true feathers that were similar to modern birds'. However, Avisornis was never able to fly, and the feathers were used for both insulation and display. Scavenging Behavior The Avisornis had a strong sense of smell, which could be used to scent carrion from about a mile away. It was also found out that an Avisornis bite mark was found on the crest of a hadrosaur. Avisornis bite marks have been found in the same area on different fossils as well, and it is known that an Avisornis would eat the fresher, juicier meat on a freshly-killed hadrosaur instead of going straight for where the meat is stringiest. This proves that Avisornis did scavenge if desperate. Pack Behavior When first discovered, it was thought that Avisornis lived in herds of thousands. Then, it was found out that the Avisornis cluster on Raptor Island was caused by a flash flood, where Avisornis were swept to the fossil sight seperately. Different fossils, however, prove that Avisornis did live in packs of about four, five, or six members, enough to help bring down large prey. Growth It was found out that Avisornis grew rapidly. It reached maturity at about four years of age. Based on color tests, Avisornis feathers changed color during different times during their lives. The juveniles were either solid white or patched with yellow, depending on gender. As sub-adults, the males' feathers would start turning a light, iridescent blue, and dull orange rings would start appearing on their tails. Females would start turning a grayish-brown. By adulthood, males were dark blue with bright yellow rings on their tails and body, and females were grayish-brown and flecked with black. Mating Avisornis mate during the late spring seasons, Late April/Early to Late May. The males let out a mating call, and a female nearby usually locates the male. The male shows off his feathers and does a courtship dance. If the female is impressed by his act, she'll join in the dance after a while. If not, she'll growl and turn away. Avisornis mate for life. Nesting Avisornis lay around 10-14 eggs in each clutch, though some nests were found with less. It is thought predators broke or ate some of them. The Avisornis usually sit on the nest, but from time to time will cover it with stray feathers, ferns, or other objects that are able to be used to keep the eggs warm. The eggs hatch in about a month, and for the next five weeks, the mother cares for her hatchlings. At five weeks, at the verge of becoming sub-adults, the juvenile Avisornis are abandoned by their mother. Paleoecology Avisornis lived in lush, lakeside forests. Hadrosaurs were abundant in the area, and made up Avisornis's main diet. Pterosaurs such as Compsogpterus and Leptopteryx were numerous around the lakes, where they preyed on fish and insects. Plants in the area included cycads, conifers, ferns, and some of the first primitive flowering plants. However, this area was prone to floods during the rainy season, which resulted in habitat destruction and the finely-preserved Avisornis fossils. Trivia -Avisornis's name means "bird bird." - There are three species of Avisornis: A. laramidiensis, A. appalachiensis, and A. australiensis. - Avisornis was originally named "Troonychosaurus", until the paleonotologists found out a troodontid from the same island had already been named that.Category:Dromaeosaurs Category:Raptor Island Life Category:Fan-made Species Category:Dinosaurs Category:Theropods Category:Maniraptoria Category:Raptors